title: Neonatal agonism of ERalpha masculinizes serotonergic (5-HT) projections to the female rat ventromedial nucleus of the hypothalamus (VMN) but does not impair lordosis.
abstract: Serotonin (5-HT) is known to play a role in the suppression of the lordosis response in males. We have previously shown that there is a sex difference in the density of 5-HT immunoreactive (5-HT-ir) fibers in the ventrolateral division of the adult ventromedial nucleus of the hypothalamus (VMNvl) and that neonatal administration of estradiol (E2) increases 5-HT-ir in the female VMNvl to male-typical levels. Here we demonstrate that postnatal administration of the ERalpha agonist 1,3,5-tris(4-Hydroxyphenyl)-4-propyl-1H-pyrazole (PPT), but not the ERbeta agonist diarylpropionitrile (DPN), also masculinizes 5-HT-ir in the female VMNvl, suggesting a mechanistic role for ERalpha in this process. Sexual receptivity, as ascertained by the lordosis quotient, was unaffected by either PPT or DPN treatment but nearly abolished by estradiol benzoate (EB), a synthetic estrogen with high affinity for both ERalpha and ERbeta. Collectively, these observations show that postnatal estrogens increase the density of 5-HT projections to the VMNvl via an ERalpha dependent mechanism, but that this increased inhibitory input is not sufficient to suppress the lordosis response.
authors.affiliation: Department of Biology, North Carolina State University, Raleigh, NC 27695, USA. Heather_patisaul@ncsu.edu
authors.forename: Heather B
authors.initials: HB
authors.lastname: Patisaul
authors.forename: Heather B
authors.initials: HB
authors.lastname: Adewale
authors.forename: Jillian A
authors.initials: JA
authors.lastname: Mickens
mesh_terms: D000818:Animals; D000831:Animals, Newborn / Q000502:physiology*; D004958:Estradiol / Q000008:administration & dosage / Q000494:pharmacology; D047628:Estrogen Receptor alpha / Q000819:agonists / Q000502:physiology*; D047629:Estrogen Receptor beta / Q000819:agonists; D005260:Female; D008297:Male; D009434:Neural Pathways / Q000502:physiology*; D009570:Nitriles / Q000494:pharmacology; D010636:Phenols / Q000494:pharmacology; D011422:Propionates / Q000494:pharmacology; D011720:Pyrazoles / Q000494:pharmacology; D051381:Rats; D012701:Serotonin / Q000502:physiology*; D012727:Sex Characteristics; D012726:Sexual Behavior, Animal / Q000502:physiology*; D014697:Ventromedial Hypothalamic Nucleus / Q000502:physiology*
chemical_list: C486182:2,3-bis(4-hydroxyphenyl)-propionitrile; D047628:Estrogen Receptor alpha; D047629:Estrogen Receptor beta; D009570:Nitriles; D010636:Phenols; D011422:Propionates; D011720:Pyrazoles; C486184:4,4',4''-(4-propyl-((1)H)-pyrazole-1,3,5-triyl) tris-phenol; D012701:Serotonin; D004958:Estradiol